FIG. 11 illustrates, as one example of a conventional solid-state imaging apparatus, a solid-state imaging apparatus 900 in which a plurality of sets of color filters 972r, 972g and 972b are arranged. As illustrated in FIG. 12, the solid-state imaging apparatus 900 includes: a semiconductor substrate 910 that includes an n-type silicon substrate 912 and a p-type well region 914; an insulating film 920 formed on the semiconductor substrate 910; a plurality of lower electrodes 930 formed on the insulating film 920; a photoelectric conversion film 950 formed on the lower electrodes 930; and an upper electrode 960 formed on the photoelectric conversion film 950. The solid-state imaging apparatus 900 further includes: a protection film 970 formed on the upper electrode 960; a color filter 972 formed on the protection film 970; and a micro lens 974 formed on the color filter 972. In the well region 914, n-type charge storage units 916 and signal reading units 918 for reading signal charges from the charge storage units 916 are formed. In the insulating film 920, a plurality of plugs 922 made of a conductive material are embedded. The lower electrodes 930 are formed in separation from each other by gaps 932, and in correspondence with a plurality of pixels respectively. The potential of the lower electrodes 930 is not fixed, and they are in the floating state.
When a positive pulse is applied to the upper electrode 960, signal charges generated by the photoelectric conversion film 950 are transferred, passing through the lower electrodes 930 and the plugs 922, to the charge storage units 916 and are stored therein. The signal charges stored in the charge storage units 916 are read by the signal reading units 918 after a predetermined time period of storage. Subsequently, the signal charges are output to outside via an amplifier.
Meanwhile, regions of the photoelectric conversion film 950 located on the gaps 932 between the lower electrodes 930 are lower in electric field intensity than regions of the photoelectric conversion film 950 located on the lower electrodes 930. This causes the signal charges to move slower in the regions of the photoelectric conversion film 950 located on the gaps 932 between the lower electrodes 930, and to be read into a frame that comes later than the originally expected frame. In that case, an afterimage may be displayed. Patent Literature 2 discloses a structure for solving this problem where the gaps between adjacent lower electrodes 930 are each set to at most 3 μm in width (namely, distance between adjacent lower electrodes).